text: The geometries of polynuclear clusters can range in complexity. A descriptor e.g. tetrahedro or the CEP descriptor e.g. Td-(13)-Δ-closo] can be used. this is determined by the complexity of the cluster. Some examples are shown below of descriptors and CEP equivalents. (The CEP descriptors are named for Casey, Evans and Powell who described the system.
  Examples:
  decacarbonyldimanganese 
  bis(pentacarbonylmanganese)(Mn—Mn)
  dodecacarbonyltetrarhodium 
  tri-μ-carbonyl-1:2κC;1:3κC;2:3κC-nonacarbonyl-
  1κC,2κC,3κC,4κC-[T-(13)-Δ-closo]-tetrarhodium(6 Rh—Rh)<br />
  or tri-μ-carbonyl-1:2κC;1:3κC;2:3κC-nonacarbonyl-
  1κC,2κC,3κC,4κC-tetrahedro-tetrarhodium(6 Rh—Rh)